Commit 581dd2dc authored by Luiz Augusto von Dentz's avatar Luiz Augusto von Dentz
Browse files

Bluetooth: hci_event: Fix using rcu_read_(un)lock while iterating 



The usage of rcu_read_(un)lock while inside list_for_each_entry_rcu is
not safe since for the most part entries fetched this way shall be
treated as rcu_dereference:

	Note that the value returned by rcu_dereference() is valid
	only within the enclosing RCU read-side critical section [1]_.
	For example, the following is **not** legal::

		rcu_read_lock();
		p = rcu_dereference(head.next);
		rcu_read_unlock();
		x = p->address;	/* BUG!!! */
		rcu_read_lock();
		y = p->data;	/* BUG!!! */
		rcu_read_unlock();

Fixes: a0bfde16 ("Bluetooth: ISO: Add support for connecting multiple BISes")
Signed-off-by: default avatarLuiz Augusto von Dentz <luiz.von.dentz@intel.com>
parent 4d94f055

net/bluetooth/hci_event.c

+11 −22
Original line number Diff line number Diff line
@@ -6870,38 +6870,27 @@ static void hci_le_create_big_complete_evt(struct hci_dev *hdev, void *data, 
		return;



	hci_dev_lock(hdev);

	rcu_read_lock();



	/* Connect all BISes that are bound to the BIG */

	list_for_each_entry_rcu(conn, &hdev->conn_hash.list, list) {

		if (bacmp(&conn->dst, BDADDR_ANY) ||

		    conn->type != ISO_LINK ||

		    conn->iso_qos.bcast.big != ev->handle)

	while ((conn = hci_conn_hash_lookup_big_state(hdev, ev->handle,

						      BT_BOUND))) {

		if (ev->status) {

			hci_connect_cfm(conn, ev->status);

			hci_conn_del(conn);

			continue;

		}



		if (hci_conn_set_handle(conn,

					__le16_to_cpu(ev->bis_handle[i++])))

			continue;



		if (!ev->status) {

		conn->state = BT_CONNECTED;

		set_bit(HCI_CONN_BIG_CREATED, &conn->flags);

			rcu_read_unlock();

		hci_debugfs_create_conn(conn);

		hci_conn_add_sysfs(conn);

		hci_iso_setup_path(conn);

			rcu_read_lock();

			continue;

	}



		hci_connect_cfm(conn, ev->status);

		rcu_read_unlock();

		hci_conn_del(conn);

		rcu_read_lock();

	}



	rcu_read_unlock();



	if (!ev->status && !i)

		/* If no BISes have been connected for the BIG,

		 * terminate. This is in case all bound connections